Feeding mechanism for sewing machines



M. L. WATERMAN 1,916,180

FEEDING MECHANISM FOR SEWING MACHINES F1181 Ap1-11 e, 1951 2sheets-sheet 1 Qwomtov Maxl, Wazerman June 27, 1933.

June 27, 1933.

M. L. WATERMAN FEEDING HECHANISM FOR SEWING MACHINES Filed April 9, 19312 Sheets-Sheet 2 ax L, yafermab Patented June 27, 1933 UNITED sTATrsATNT "oli-*FICE MAX L. WATERMAN, or FAIRFIELD, coNNnoTIoUT, AssIeNon Touma `SINGER MANU- FAoTUnING COMPANY, or ELIZABETH, NEW massif, ACORPORATION oF NEW JERSEY FEE-DING MECHANISM FOR SEWING MACHNESApplication fled April 9,

This invention relates to improvements in work-feeding mechanisms forsewing machines and more particularly in upper fourmotion mechanisms ofthis character in which a work-advancing feeding-foot and a work-holdingpresser-foot are vertically reciprocated to alternately engage the work.l In upper four-motion feeding mechanisms of the character commonlyknown as the alternating-presser type, there is employed an automaticpresser and feeding-foot lifting mechanism which is normally dependentupon the resistance imposed by the work or its support to the downwardmovement of i either the presser-foot or feeding-foot in order toprovide a fulcrum for lifting the other of said members. Obviously, ifany cramping or inertia of the parts occasions a sumcient resistancebefore either of said members in its descending movement reaches thework7 the necessary fulcrum will be untimely pro- 1 vided and neither ofsaid members will engage the work with the requisite pressure to insureadvancing the work the necessary eX- tent to effect the production ofstitches of uniform length. The liability of imperfect operation ofprior feeding mechanisms of this character increases with the speed ofoperation of the machine, due in a large measure to inertia of theparts, and at high speeds a degree of ineiciency may be reached Whereinneither the presser-foot nor the feedingfoot perceptibly engages thework.

The present invention therefore has forv its primary object to improvethe work-advancing efficiency of upper four-motion feeding mechanismsfor sewing machines under operation at high speed and attains thisobject by the provision of feed-actuating mechanism designed to insurealternate engagement of the work with the requisite pressure by thefeeding-foot and the presser-foot.

In accomplishing the object of the inven-l tion, the feeding-foot andpresser-foot are alternately raised above the work by mechanism designedto minimize cramping action of the presser-foot and feeding-footcarrying bars in their bearings, and the feeding-foot and presser-footbars are individually subjected to spring pressure in a manner de- 1931.Serial No. 528,794.

signed to overcome inertia and also any frictional resistance to thefree reciprocation of said bars.

The invention will best be understood from the following description ofa. preferred embodiment thereof illustrated in the accompanyingdrawings, in which Fig. 1 is a View in front end elevation of thebracket-arm head of a sewingL machine having the im-:

proved feeding mechanism, the `work-support and'lower feed-dog beingshown in section. Fig. 2 is an enlarged detail view partly in section,of theneedleyand feed-bars, illustratiiig the spring arrangement fordepressing the feed-bar. 3 is a horizontal section of the front end ofthe machine bracketarm substantially along the axis of theneedie-actuating shaft journaled in said bracketarm. Fig. 4 isa rearside elevation, partly kin section, ofthe freeend of the machinebracket-arm.

Referring to the drawings, the present 1mprovenients are shown asembodied in a commercially well `known sewing machine having awork-support comprising a cloth-plate i 1 and a throat-plate 2 providedwith a feedslot 3 in which operates a lower four-motion feed-dog thaving a needle-aperture 5.

Overhanging the work-support is a brach--I et-arm 6 terminating at itsfree end in a head 7, in which bracket-arm is suitably journaled therotary main shaft 8 carrying a crank-disk 9 connected in theusual mannerby means of a link 10 with a collar 11 se- Y cured upon a needle-bar 12carrying a needle 13. The needle-bar 1 2 is journaled for endwisereciprocation in vertically alined apertures provided lin bearing lugs14 of a vibratory frame 15 which ispivotally support-l ed at its upperend forv jogging movements about an axis substantially parallel with themain-sliaft 8, the pivotal supporting means for saidiframe comprising afulcrum-pin 16 fixed in the bracket-arm head by a set-screwl f expedientdisclosed, for instance, in the U. S. patent to J. C. Ringe, No.1,685,436, Sept. 25, 1928. In Fig. 1 of the drawings herewith is shownin dotted lines the usual rock-shaft 1S having its crank-arm 19operatively connected with the lower of the vibratory-frame bearing-lugs14 for the purpose of jogging the frame.

The lower' of the bearing-lugs 14 is also provided with a verticallydirected bore 2O slidingly receiving a tubular feed-bar 21 upon thelower end of which is suitably secured the shank of a feeding-foot 22preferably having a serrated work-engaging face. The feeding-foot 22 isapertured to provide a passageway for the needle, and as both theneedlebar and the feed-bar are journaled in the vibratory frame 15, itis evident that the needle partakes of the work-advancing and returnmovements of the feeding-foot, which latter and also the lower feed-dogserves to reinforce the needle against lateral stresses while in theWork.

The feeding-foot is yieldingly urged toward the work-support by theaction of a 'coil-spring 23 interposed between the upper end of thefeed-bar 21 and an abutment 24 in the present case integral with aguide-rod 25 embraced by the spring 23. The lower end of the guide-rod25 slidingly enters the bore of the tubular feed-bar 2l and its upperend is guided by an apertured ear 26 projecting from the vibratory frame15, whereby said guide-rod 25V also partakes of the jogging movements ofsaid frame. The rounded upper end of the guide-rod 25 is seated in thecupped end of an adjusting-screw 27 threaded through the bracket-armhead of the machine frame and secured in adjusted position b v means ofanut 2S. The close proximity of the cupped end of the adjusting screw 27to the fulcrum-pin 16 obviates any liability of unseating of the rod 25during normal jogging movements of the frame 15.

Projecting laterally from the headed upper endr of the feed-bar 21 is astud 29 pivotally embraced by 'an apertured ear 30 at the lower end of avertically directed link 31, of which the ripper end has a stud 31pivotallv connected with an arm 32 of a two-armed lever 32. 33.' Thelever32, 33 has intermediate its ends a hub 34 apertured transversely ofthe length of the lever to receive a fulcrum-pin 35 projectinglaterallyl from an arm 36 of a fulcrum-block 37. clamped by means of ascrew 38 upon the usual presser-bar 39. The presser-bar is verticallyreciprocable in bushings 40 and 41 fixed in the machine bracketarm head,said presser-bar being restrained in the usual manner against turning insaid bushings and carrying at its lower end a presser-foot 42 alsopreferably provided with a serrated work-engaging face. In the presentcase, the lever-arms 32 and 33 are in substantial alinement and aredisposed substantially normal to the vertical path of movement of thepresser-bar.

The free end of the lever-arm 33 carries a stud 43 pivotally embraced byan apertured boss 44 upon the lower end of a bent link 45 of which theopposite end also carries an apertured boss 46. The link-'boss 46pivotally embraces a screw-stud 47 threaded into a crank-arm 48 upon oneend of a horizontally disposed rock-shaft 49 journaled in bearing lugs5() at the rear side of the machine bracket-arm, said rock-shaft 49being substantially parallel with the main-shaft 8. Clamped upon therock-shaft 49 by a screw 51 is the split hub of another crank-arm 52pivotally connected with one end of a pitman 53 of which the oppositeend has a strap 54 embracing an eccentric 55 suitably secured upon themain-shaft 8.

The presser-bar is as usual yieldingly depressed by a flat spring 56,disposed at the rearfside of themachine'bracket-arm and overlying a lug57 of a split-collar 58 clamped upon the presser-bar by a screw 59. Thefulcrum-block 37, previously referred to, has the usual lifter-arm 60underlying which is the angular wear-plate 61 interposed between thelifter-arm 6() and a lifter-lever 62 pivotally secured by a screw 63upon the rear side of the machine bracket-arm. A portion ofthel foot 42being raised lclear of the work-support. As the feed-members approachthe end of their work-advancing movement, the rockshaft 49 is actuatedin aI direction to lower the free end of the crank-arm 48 rtherebyswinging the lever 32, 33 about a fulcrum constituted by the pivot-stud3l of the link This swinging movement of the lever 32, 33, aided by theaction of the spring 56 results in a downward movement of thepresser-bar 39 which is arrested by the worksupport or the workthereupon at substant-ially the completion of the work-advancingmovement of the feeding-foot. The fulcrum of the lever 32, 33 is nowautomatically shifted from the pivot-stud 31 to the fulcrum-pin 35 andconsequently the further downward movement of the link 45 rocks thelever 32, 33 about the fulcrum-pin 35, thereby lifting the feeding-foot22 against the action of the spring 23, said feeding-foot while liftedclear of the work being returned to its forward position by the returnjogging movement of the frame 15. The rock-shaft 49 is now oscillated`in the opposite direction by the eccentric 55, thereby rocking the lever32, 33 in the opposite direction about the fulcrum-pin to edect adownward movement of the pivot-stud 31 and consequently lowering thefeeding-foot 22 with the aid of the spring 23 into its initial position.

While it will be understood from the foregoing description that thepresent feeding mechanism resembles prior mechanisms of this characteras to its general mode of operation, it will be observed that the alinedrelationship of the lever-arms 32, 33 and the disposition thereofsubstantially perpendicular to the presser-bar 39 lessens considerablyany effect to cramp the presser-bar in its bearings upon actuation ofsaid lever. Although the operating conditions are thus materiallyimproved by the described mechanism for actuating the presserandfeedbars, both the feeding-foot 221 and the presserfoot 42 fail toproperly perform their functions of advancing the work and of holdingthe advanced work, when said feeding-foot and presser-foot do not engagethe work with the requisite pressure. At high speed operation, theinertia. of the presserand feedbars together with any frictionalresistance to their reciprocation retards the downward movements of saidbars to such an extent that the presser-foot and feeding-foot barelyengage the work and may in fact walk entirely above lthe work. Byproviding the spring 23 to act downwardly upon the feed-barindedependently of the presser-bar, the inertia tendencies areeffectively overcome without materially affecting the pressuredistribution which may be determined by individual adjustment of thepresser-bar and feed-bar springs. The requisite adjustment of thefeed-bar spring 23 is obtained by the screw 27 threaded into the machineframe to afford a rigid abutment for the spring and to provide forconveniently `effecting the adjustment.

Having thus set forth the nature of the invention, what I claim hereinis l. The combination in a sewing machine having a frame including aVwork-support, a reciprocatory presser-foot carrying bar, a feeding-footcarrying bar mounted for endwise reciprocatory and laterally joggingwork-feeding movements, means for reciprocally actuating said bars indirections toward and from said work-support, and springs reactingagainst said frame thrusting individually upon said presser-foot andfeeding-foot carrying bars to yieldingly urge said bars toward thework-support.

An upper feeding mechanism for sewing machines including, incombination, a work-support, an endwise.k reciprocatory presser-footcarrying bar, a spring acting to yieldingly urge said presser-footcarrying bar in a direction toward the work-support, a feeding-footcarrying bar mounted for endwise reciprocatory and laterally joggingwork-feeding movements, a lever having pivotal connections with both ofsaid bars, means for rocking said lever to reciprocally actuate saidbars toward and from the work-support, and a spring acting upon thefeedingfoot carrying bar and compressed by the movement yof thefeeding-foot carrying bar in a direction away from the work-supportLinder the action of said lever.

. 3. The combination in a sewing machine having a frame including awork-support, a reciprocatory presser-foot carrying bar, a feeding-footcarrying bar mounted for endwise reciprocatory and laterally joggingywork-feeding movements, a lever pivotally connected with both of saidbars having its arms in substantial alinement and disposed substantiallynormal to the path of reciprocatory movement of said presser-footcarrying bar, means for roclrinfr said lever to reciprocally actuatesaid bars toward and from the work-support, and springs thrustingindividually upon said presser-foot carryingk bar andfeeding-foot-carrying bar to yieldingly urge said bars toward thework-support.

4. rlhe combination in a sewing machine having a frame including awork-support, a reciprocatory presser-foot carrying bar, a feeding-footcarrying bar, a jogging frame in which said feeding-foot carrying bar isjournaled for endwise reciprocation, means for reciprocally actuatingsaid bars in directions toward and from said work-support, springsreacting against the machine frame and thrusting individually upon saidpresserfootcarrying bar and feeding-foot. carrying bar to yieldinglyurge said bars toward the work-support, and means for supporting one ofsaid springs upon said jogging frame for vibrator-y movements therewith.

5. An upper feeding mechanism for sewing machines including, incombination, a work-support, an endwise reciprocatory presser bar, apresser-foot carried by said presser-bar in directions toward and fromthe work-support, a tubular feed-bar, a feeding-foot carried by saidfeed-bar, a jogging frame in which said feed-bar is ournaled for endwisereciprocation, a guide-rod slidingly entering the tubular feed-barhaving an abutment, a spring' interposed between the abutment of saidrod and said feed-bar acting to urge the feed-bar ina direction towardthe work-support, adjustable stationary means opposing the thrust ofsaid guiderod in a direction away from said feed-bar, and means forreciprocally actuating the presser-bar and feed-bar in directions towardand from said work-support.

ln testimony whereof I have signed my. name to this specification.

MAX L. WATERMAN

